Carburetor



Oct. 31, 1933. c M K T AL 1,933,330

CARBURETOR Filed April 21, 1930 5 Sheets-Sheet l I N V EN TORS flank C.Mock ()Ct. 31, 1933. F c, MOCK r vAL 1,933,380

CARBURETOR Filed April 21, 1930 3 Sheets-Sheet "2 IN VEN TORS" Frank C.Heck Oct. 31, 1933. F, c MOCK ET AL 1,933,380

CARBURETOR Filed April 21 1930 s Sheets-Sheet 5 INVENTORS Frank C.jfl'fock flwan 15. Chandler Patented Oct. 31, 1933 CARBURETOR Frank C.Mock and Milton E. Chandler, Chicago,

Ill., assignors to Bendix Stromberg Carburetor Company, South Bend,Ind., a corporation of Illinois Application April 21, 1930. Serial No.445,922 8 Claims. (Cl. 261-439 This invention relates to carburetors andmore particularly to means for controlling the path of air flow, andfuel spray flow, in carburetors and in the intake passages of internalcombustion engines.

In automobile engine practice in particular, it is common to have theair entrance of the carburetor at an angle to the direction of air flowpast the jet. This results in the air flow not filling the airpassage,with consequent low capacity of air flow and the formation of eddycurrents which have the effect of pulling the fuel spray out of thecenter of the air stream. Also, if the inequality of air flow extends asfar asa point of division in the engine intake manifold, a condition ofunequal pressures is formed, which tends still further toward inequalityin the air stream distribution.

Such a condition manifests itself in the operation of the engine, aslack of smoothness, very narrow range of permissible mixture proportion,high fuel consumption and an unusual tendency to miss or backfire whenthe throttle is opened quickly. Also, the engine will usually pullbetter and smoother with the throttle partly closed than with it fullopen. All the circumstances causing this are not fully understood, butour experiments have repeatedly shown that the engine performance isvery much better when the air stream, as measured by Pitot search tubes,is uniform across the section of the carburetor barrel, and when thefuel spray is then evenly and centrally distributed in the air stream.

An object of our invention is to provide a means whereby the air passingthrough a carburetor is given a smooth stream line flow of substantiallyuniform velocity, and free from eddy currents. A further object of ourinvention is to provide a means for preventing distortion of currents in40 the air flow through the passages of a carburetor and intake manifoldof the engine.

Another object of our invention is to provide a means whereby the airflow through a carburetor and the intake manifold to the engine isuniform across the section of the air passage.

Still another object of. our invention is to provide a means whereby thefuel spray in a carburetor is evenly and centrally distributed in theair stream passing through the carburetor.

With these and other objects in view, which are incidentto ourimprovements, our invention consists in the combination and arrangementof parts hereinafter described and illustrated in the accompanyingdrawings, in which the same referenge numerals denote similar elementsthroughou Figure 1 is a vertical longitudinal section of a plain tubetype of carburetor embodying our improvements;

Figure 2 is a section along the line 2'2 of Figure 1, looking in thedirection of the arrows;

Figure 3 is a vertical longitudinal section of a modified form of ourinvention; and

Figure 4 is a similar view of still another modification of ourinvention.

Referringv toFigures 1 and 2, the numeral 1 designates the body of acarburetor, 2 an engineintake manifold which is bolted to the carburetorby means of a usual flanged joint 3. A Venturi tube 4 and throttle valve5 are positioned in the carburetor body 1, as clearly shown. A multiplejet' nozzle 6 is threaded through the bottom wall of the carburetor body1 so that the jets discharge in the zone of the smallest section ofVenturi tube 4.. A constant level float chamber 7 supplies liquid fuelto nozzle 6 through a submerged metering orifice 8.

Cast integral with the carburetor body 1, is an intake air horn 9arranged substantially at a right angle with the body 1. Air horn 9 hasa flat square bottom wall 10 and back wall 11 which intersect insubstantially a right angle, only the extreme junction'angle beingrounded off, as at 12. It will be noted that the back wall 11 of the airhorn is bulged out so as to enlarge the section of the 'elbow turn to asize greater than the section of the body 1, and thatthis wall mergeswith body 1 in a curve which is continuous with that of the Venturi 4.The same is true of the inner curved wall 13 joining the upper wall ofair horn 9 with body 1. In this way a continuous stream line surface issecured and no projections or interrupting surfaces are presented todisturb the air currents passing through the carburetor. Positionedwithin the air horn 9 are a plurality of guide vanes or partitions 14which commence in planes parallel to the axis of air horn 9, continuearound the elbow bend, and terminate in planes at right angles to theaxis of air horn 9 just below venturi 4. These guide vanes 14 areequispaced at all points so that the channels defined by them are of thesame cross section along any intersecting plane.

vided a plurality of vertical guide vanes or partitions 15, whichfurther equally subdivide the channels defined by partitions 14.Partitions 14 and 15 may be cast integral with air horn 9 and body 1, asshown in Figures 1, 2 and 3, or they may be separate therefrom,as inFigure 4 where they are formed integral with the Venturi tube.

In Figures 1 and 2, we have shown our preferred embodiment. Here thevanes or partitions used to conduct the air flow around the angle of theair horn are preferably in the form of conjugate hyperbolas tofacilitate stream line flow. We have also found that vertical vanesparallel to the plane of the bend are helpful in breaking up vorticesthat tend to form from the corners where the firstmentioned ribs jointhe wall of the air passage. The shape and arrangement of these ribswere determined by experimenting with a Pitot search tube whilea'current of air is forced through the carburetor.

In Figures 3, we have illustrated a modified form of our invention,wherein the partitions 14 are reduced to small curvilinear guide vanesspaced equally across the plane of junction of the horizontal andvertical walls of air horn 9. The channels thus defined by these vanesare of equal cross section.

Referring again to Figures 1 and 2, the numeral 16 denotes a detachablesection of the engine intake manifold 2, which section is formed with aplurality of deflecting ribs or vanes 17 which define channels of equalcross section around the bend from the carburetor body 1 to the manifoldbody 2. These ribs or vanes 1'7 perform with the outgoing mixture thesame function as is performed by partition 14 on the incoming air. Bydefining smooth stream line channels of equal cross section, a steadyflow of uniform velocity is obtained and unequal pressures and eddycurrents are eliminated. This helps greatly to prevent liquid fueldeposits on the walls of the intake manifold.

It will be noticed that Figure 1 shows a fuel jet 6 having a submergedmetering orifice 8 and larger multiple outlets arranged so that the fuelspray is not directed against the throttle valve 5 and its shaft. Thisadvantageous form of jet can only be used with an air flow so even thatthe suction is equally balanced on the jet outlets. With theconventional elbow air passage, the suction would not be equal on thetwo outlets, consequently such a jet would discharge a large butuncertain proportion of its fuel from the outlet located in the highestair velocity.

With the manifold vanes shown in Figures 1 and 2, even and straightdischarge of air and fuel spray may be obtained at the point of divisionof the manifold above the carburetor. Provided the fuel and air streamare equally spread across the outlet of the carburetor, this equalitymay be maintained by suitably formed guide vanes 1'7. These vanes extendinto the manifold from a plate-like cover 16, the purpose of thisconstruction being to permit more accurate forming of the vanes bycasting the piece in a die casting or metallic mold. It is to be notedthat the vanes 1'7 are so located with respect to the throttle valve 5that a plane including the throttle axis and the axis of the mixingchamber bisects each of the vanes, so that when the throttle is in partopen position, the two halves into which it divides the air stream willeach be distributed uniformly among the manifold channels formed by thevanes.

By the provision of guide vanes in the air horn and intake manifold,square elbows may be used with greater efficiency than curved elbowswithout the vanes. We have also found that the enlarged square elbowshown in the air horn in Figure 1 is more eificient than the usualrounded elbow even without the vanes, although the vanes still furtherincrease its efficiency.

While we have disclosed the preferred form of our invention, we desireit to be understood that We do not intend to be limited to the preciseform, which for purposes of illustration, we have shown and describedherein, as many changes in details of construction, form and arrangementcan be madeby those skilled in the art without departing from the spiritof our invention or exceeding the scope of the appended claims.

We claim:

1. In a carburetor having a body and an air horn at an angle, aplurality of curvilinear guide vanes extending from near the entrance tosaid air horn to said body and subdividing said air horn. into aplurality of smooth curvilinear channels whereby a condition of steadyuniform air flow is maintained.

2. In a carburetor having a body with an air passage therethrough, anair horn having a square elbow of enlarged cross section as compared tosaid passage and a plurality of guide vanes subdividing said air passageinto channels.

of substantially equal cross section.

3. In a carburetor having a curved air passage, aplurality of curvedguide vanes paralleling the walls of said air passage and subdividingsaid passage into channels of substantially equal cross section.

4. In a carburetor having a curved air passage, a plurality of curvedhorizontal vanes paralleling the walls of said passage and subdividingsaid passage into channels of substantially equal cross section.

5. In a carburetor having an air passage, a plurality of intersectinghorizontal and vertical partitions subdividing said passage intochannelsof substantially equal cross section whereby a steady uniform flow ofair through said passage is secured.

6. The combination of a carburetor having a throttle valve and adischarge pipe therefor having a plurality of guide vanes subdividingsaid pipe into channels, said vanes being in planes perpendicular -totheplane of said throttle axis, so that when 'said throttle is in part openposi tion it does not interferewith the effect of said vanes on theair-fuel mixture passing through said discharge pipe.

'7. In a carburetor having a curved airinlet, a plurality ofintersecting partitions subdividing said inlet into channels to providea uniform flow of air through said inlet.

- 8. In a carburetor having an elongated mixing chamber and a throttlevalve pivoted therein, a discharge pipe leading from the mixing chamber,and a plurality of guide vanes subdividing said pipe into channels, saidvanes being so positioned that a plane including the axis of the mixingchamber and the throttle axis bisects each of the vanes.

IVULTON E. CHANDLER. FRANK C. MOCK.

